Upbeat nystagmus changing to downbeat nystagmus with convergence

A 35-year-old woman developed upbeating nystagmus while recovering from presumed Wernicke-Korsakoff syndrome. The upbeating nystagmus changed to downbeating nystagmus with convergence. The slow-phase velocity of the downbeating nystagmus varied with the convergence effort. We believe that this unusual nystagmus pattern implies convergence input to the supranuclear centers for vertical gaze.